Although the "Clayton-Bulwer Treaty" signed by Britain and the United States in 1850 stipulated that the two countries should not seek any expansion in the Central American region, the American intervention in the internal affairs of Central America did not stop after gaining local advantages.

The southern expansionists did not accept the treaty signed with Britain and continued to pursue a policy of "destiny" and unlimited expansion.

Nicaragua's liberals suffered a defeat in the civil war of 1845. With the active support of the Americans, they organized an expeditionary force on the territory of the United States, ready to return to politics.

Adventurer William Walker is a mercenary known as the "Liberation Movement" who is hired by the Nicaraguan uprising to "liberate" the Central American country.

Walker and the "Liberation Movement" invaded and ruled Nicaragua in 1855. Instead of handing over power to the Nicaraguans who hired him, Walker established a personal dictatorship and was ready

Start with Managua, conquer all of Mesoamerica.

In the face of protests from Central American countries and Britain, the United States claimed that it did not take any responsibility for the incident and that Walker acted without regard for the law. However, the support for the Liberation Movement in influential economic circles in the southern United States is open and obvious, and it is also open and obvious that American leaders and the press view this support with sympathetic eyes.

All of Central America united against Walker, known as the "War of the Liberation Movement", and expelled him from the isthmus in 1857. However, the leader of the Liberation Movement did not give up and invaded Central America for the second time in the same year. This time, he had to withdraw again.

In 1860, he invaded for the third time, but this time he was confronted by a British navy to defend the territorial integrity of Central America, and Walker was captured by the British. The British handed him over to the Central Americans to be shot.

During this period, the United States was intensifying its activities in preparation for the occupation of the island of Cuba, and from Jefferson onwards, the United States had a strategic plan to annex Cuba. John?? Quincy Adams had tried to keep Cuba under weak Spanish rule so that it could be "a ripe fruit" in the hands of the United States in the future.

Navy Colonel Mahan, an American geopolitical theorist and then president of the U.S. Naval Academy, stressed the importance of U.S. domination of nearby islands and seas.

Before Mahan proposed the theory of sea power, President Polk had purchased Cuba for $100,000 in 1848. From 1849 to 1850, Narciso López, who was supported by the southern United States, tried to liberate Cuba from the Spaniards and then annex it to the United States. In 1853, Liberal President Fillmore stepped down, and the Democratic Party returned to power in the United States. Pierce was president. When Pierce took office, he pledged to "never leave the expansionist path" and his government wanted to buy the island of Cuba. In 1854, the United States offered $130 million while threatening Spain with a recent maritime incident. Spain was determined not to sell its most precious colony.

Strong political pressure from the south of the United States demanded an armed invasion of the island. Dixie's hacienda owners and merchants spread rumors that Britain planned to seize Cuba, free slaves, and establish an "Africanized republic" that would form the basis of the anti-slavery uprising in the United States.

As part of this pressure, the three U.S. ministers plenipotentiaries to European countries, after meeting in the Belgian city of Ostend, sent a memorandum to President Pierce recommending the conquest of Cuba by force.

On the island of Cuba itself, the Havana Club, which politically spoke on behalf of the sugar-producing oligarchs, favored the expulsion of the Spaniards and the United States, working closely with the supporters of slavery in the southern United States.

However, the Cuban middle class opposed the pro-American elements, and their politically minded activists were divided into two factions: the autonomy faction, which demanded greater political autonomy for the island and not complete independence from the Spanish suzerainty; The other faction is patriotic, advocating the creation of a "Cuban Cuba" without any foreign domination.

In 1869, the patriotic movement gained enough strength and support to hold a large-scale armed uprising against Spain. Internationally, Britain and France supported Spanish rule over the American colonies and operated Cuba as the core line of defense to contain American expansion, so the insurrectionary movement ultimately failed, and the Americans did not wait for the right opportunity to occupy the Cuban colonies.

The key to the seizure of Cuba was the strength of British and French support for the Kingdom of Spain, and under the current situation of the coordination of Britain, France, and Spain, the US government, in order to counter Britain's sabotage of the International Conference of the Americas, temporarily resisted its ambition to attack Cuba, and turned the spearhead of expansion directly at the Caribbean Sea and the northern part of South America.

On January 21, 1889, led by the United States, representatives of eight countries, including the six Central American countries of Guatemala, Belize, El Salvador, Honduras, Nicaragua, Costa Rica and Mexico, signed a trade agreement, announcing the establishment of the Inter-American Customs Union.

The six Central American countries and Mexico are no match for the Americans in the industrial and economic fields, and the reciprocal trade agreement on the surface of equality has in essence provided an excellent excuse for American capital to reasonably and legally control the economy and politics of the seven countries.

The six Central American countries cover an area of about 500,000 square kilometers. The population is about 4 million, mostly of Indo-European people,

In the economic field, except for the cane sugar field, which has a relatively long history of cultivation, which is controlled by Western countries,

More than 70 percent of the industries related to the national economy, such as cotton, tobacco, cocoa, sisal, grain farming, cash crop planting, animal husbandry, forestry, food processing, and mining and smelting of mineral resources, are in the hands of US capital.

The formation of the Inter-American Customs Union means that the Americans have completed the final step of complete control of Central America.

After the news of the signing of the agreement between the eight governments was officially released, the US government made a number of countermeasures non-stop.

The first is to impose an armed blockade on Tolti Island, where the Caribbean detachment is stationed, on the pretext of maintaining the security of the Caribbean sea trade routes and clearing the surrounding waters.

Second, on the issue of the excavation of the Isthmus of Central America, the US Government, on the one hand, demanded that the British give up their right to intervene in the construction of the canal, and on the other hand, secretly contacted the Panamanian independence elements, intending to gain independent control of the canal by instigating Panama to secede from the Republic of Colombia.

Third, on the issue of the territorial dispute between British Guiana and Venezuela, the US government took the initiative to reach out to the Venezuelan government and promised to support Venezuela's reasonable claims on the territorial issue and provide strong backing for Venezuela to deal with the threat of force from the British Empire.

British Guiana's long-standing territorial dispute with Venezuela

In 1814, Britain gained control of Guyana from the Netherlands and began to send colonial officials to administer it.

In 1831, Guyana officially became a British colony and took the name British Guiana.

After 1850, the British gradually pushed the border between Venezuela and British Guiana westward

and then into the territory that historically belonged to Venezuela in the 1880s.

Venezuela was a small and weak state, and it was no match for the British Empire in terms of force, so the colonists of British Guiana did not hesitate to face the protests of the Venezuelan side.

Venezuela is rich in mineral and untapped oil resources, and close to British Guiana, Britain's bridgehead in South America, the Americans stepped in and brought their military and political influence into northern South America, which had a completely different meaning than the previous economic expansion.

In the face of a strong counterattack by the Americans, the British government, while ordering diplomatic agencies to issue a statement on the United States with drastic measures, also ordered the army and navy stationed in British Guiana to be on increased alert and vigilant against the movements of Venezuela and the US navy.

The local government's strategic focus was on the line of Paraguay and the Republic of Brazil, and Han was separated from the United States by most of South America, and even if it learned of the hostile military action of the American fleet against the Caribbean detachment stationed on the island of Torti, the local government could not take strong countermeasures.

Britain and the United States are the two major powers that dominate the affairs of the Americas, and the Han government does not yet have the strength to directly confront the United States under the current realities.

Therefore, in the face of the struggle between Britain and the United States for dominance in the northern part of South America, the local government could only follow closely behind the British, on the one hand, they scolded the Americans in the air, and on the other hand, they gave an order to the Caribbean Sea Fleet, ordering the fleet to end the confrontation with the US Navy and immediately withdraw from the Caribbean Sea and return to the mainland for repairs after handling the transfer of the Chinese people and the arrangement of armed personnel on land.

After the local government made concessions and took the initiative to withdraw from the Caribbean Fleet, the border line of confrontation between the United States and Britain was officially pushed forward from Central America and the Caribbean to Venezuela and Colombia in northern South America.